FIELD OF THE INVENTION
This invention is directed to a novel chemical process and is particularly concerned with the production of the anti-depressive anxiolytic 1-[(dimethylamino)methyl]-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepine s.
The process of this invention can be illustratively represented as follows: ##STR2## wherein X.sup.- is the anion of a monovalent organic or inorganic acid, preferably the anions of hydrochloric, hydrobromic, and hydriodic and trifluoroacetic acid; wherein Y is nitrogen or ##STR3## in which R.sub.1 is hydrogen, chloro, or fluoro; wherein R.sub.2 is hydrogen, fluoro, chloro, bromo, trifluoromethyl, or nitro.
The novelty of this invention consists in using specific conditions with a specific reagent while applying a Mannich Type reaction to prepare as the major product compound of formula 11. The use of the Mannich reaction in this case is not new. Application Ser. No. 387,761, filed Aug. 13, 1973, now Ser. No. B 387,761, published Jan. 28, 1975, discloses the use of the Mannich reaction for the addition of an aminoalkyl group to a triazole ring. When the conditions of this invention (Ser. No. B 387,761 ) are applied to the compounds of formula I of this invention the desired products of formula II are not obtained, but instead compounds of the formula III. ##STR4## Only with the present reagent IV and the conditions further on described the compounds of formula II are obtained. The reagent used has the formula IV; ##STR5## wherein X.sup.- is any suitable anion of a monovalent inorganic or organic acid such as hydrochloric, hydrobromic, hydriodic, trifluoroacetic, acetic, tetrafluoroboric, benzoic, HPF.sub.6, perchloric, chloric, HSbCl.sub.6 and the like. Such reagents are disclosed in the art, e.g. Bohme, H, et al., Chem. Ber. 105, 2233, (1972). Bohme, H. et al., Chem. Ber. 93, 1305 (1960); Bohme, H., Tetrahedron Lett. 2785 (1972); Volz, H. and Kiltz, H., Tetrahedron Lett. 1917 (1970) and Am. Chem. 752, 86 (1971); Huisgen, R., Kolbeck, W. Tetrahedron Lett. 783 (1965); Ahond, A., et al., J. Amer. Chem. Soc., 90, 5622 (1968); Jaser, Y., Chem. Comm. 253 (1974); Eschenmoser, A., et al., Angew. Chem. Int. Ed. (Eng) 10, 330, (1971).
In order to obtain a high yield in the reaction I.fwdarw.II, , specific reaction conditions must be applied. Under other conditions the above described reagents can add at the 4-position only, or simultaneously in the 1- and 4-positions of compound I thus providing products of lesser interest than those defined by formula II.